Herbert S. Wilf: 1931-2012

Herbert S. Wilf, an innovative mathematics researcher, teacher, writer,
journal editor, and the University of Pennsylvania Thomas A. Scott
Emeritus Professor of Mathematics, died on Saturday, January 7, 2012 in
Wynnewood, Pennsylvania. The cause of death was a progressive
neuromuscular disease.

Wilf was the author of six books and more than 160 research articles.
From the 1950's, he was a pioneer in the mathematical programming of
early computers, beginning with his work at Nuclear Development
Associates, which led to his book Mathematical Methods for Digital
Computers, written with A. Ralston. From 1959 to 1962, he taught at
the University of Illinois. His early work focused on numerical
analysis and complex analysis, and led to numerous research papers as
well as a textbook, Mathematics for the Physical Sciences.

Wilf taught at the University of Pennsylvania from 1962 until his
retirement in 2006. For him, teaching and research were deeply
intertwined, and he was recognized throughout his career for exemplary
teaching. In 1973 he received the University of Pennsylvania's
Christian and Mary Lindback Award for excellence of
undergraduate teaching. In 1996 he received the Deborah and
Franklin Tepper Haimo Award for distinguished teaching of
mathematics, from the Mathematical Association of America.

In the 1960's, Wilf became interested in the newly developing field of
combinatorial analysis. He wrote fundamental research papers, forming
the foundation of today's work in discrete mathematics with its
applications to computer algorithms and its close interconnections with
the mathematical fields of algebra and probability theory. He did
pathbreaking work with D. Zeilberger of Rutgers University on a theory
of computerized proofs for combinatorial identities. For this work they
were awarded the Leroy P. Steele Prize of the American Mathematical
Society for Seminal Contributions to Research in 1998. Overall, he
contributed over 135 papers in combinatorics and wrote four influential
books, including generatingfunctionology and A = B, the latter
with M. Petkovsek and D. Zeilberger. In 2004 he was awarded the
Euler Medal for Lifetime Contributions by the Institute for
Combinatorics and its Applications. He supervised 26 Ph.D. students in
combinatorics at the University of Pennsylvania.

Wilf was a pioneer advocate of the open electronic publishing of books
and journals. Many of his books are available for free download on his
web page, www.math.upenn.edu/~wilf which
registered an astounding 350,000 downloads last year. Amazing. He
co-founded two major journals, The Journal of Algorithms in
1980 with D. Knuth, and The Electronic Journal of Combinatorics
in 1994 with N. Calkin. From 1987 to 1992 he also served as
Editor-in-chief of The American Mathematical Monthly, a leading
journal that aims for expository and readable dissemination of
mathematical work for teachers and researchers. Wilf spoke widely at
colleges, universities, and mathematics conferences throughout the
world. He was an avid amateur pilot, and often flew himself to these
occasions in his private plane.

Over his long career, Wilf co-authored research papers with more than
60 mathematicians. His final papers were as influential as his early
ones, including "There's plenty of time for evolution" with W. Ewens,
which appeared in the Proceedings of the National Academy of
Sciences in 2010. Wilf's wit shone through in some of his whimsical
paper-titles, such as "The 'Snake Oil' method for proving combinatorial
methods," and in his appreciation of articles written about his work
such as B. Cipra's "How the Grinch stole mathematics."

Herbert Saul Wilf was born on June 13, 1931 in Philadelphia, the son of
Alexander and Bertha Wilf. He received a B.S. in mathematics from the
Massachusetts Institute of Technology in 1952, and a Ph.D. in
mathematics from Columbia University in 1958. He is survived by his
wife of 59 years, Ruth Tumen Wilf, a daughter Susan, two sons David and
Peter, and six grandchildren.